The present invention relates to a method and a device for detecting a transmittivity spectrum of a light guiding plate.
With the rapid development of the display technology, liquid crystal display devices (such as liquid crystal TV sets, liquid crystal displays, liquid crystal display screens and the like) are increasingly widely used in manufacture and normal life due to it advantages of being driven with a low voltage, its flat panel structure, informative display, easy coloring, long life, no radiation and no pollution etc. However, liquid crystal display devices are display devices of a passive type, which can not emit light themselves and therefore have to modulate external light to achieve the object of displaying. Thus, backlights play a very important role in liquid crystal display devices.
A light guiding plate is one of the components which function importantly in a side light type backlight. FIG. 1 shows a structure schematic view of one example of a light guiding plate. The light guiding plate 11′ is colorless and transparent, and its bottom surface forms as an optical functional surface 10′. At least one side of the light guiding plate 11′ is designed as an incident surface 14′. Light from a light source enters into the light guiding plate 11′ through the incident surface 14′ and exits from an upper surface of the light guiding plate 11′, i.e. an exiting surface 15′ after a plurality of reflections by the optical functional surface 10′ and an inner side of the light guiding plate to form a uniform surface light source.
Due to differences in light absorptivity of the material of the light guiding plate and the optical functional surface 10′ for light with different wavelengths, and the like, the incident light of the incident surface 14′ has a different spectrum from the exiting light of the exiting surface 15′, which causes a chroma offset of the exiting light of the light guiding plate. If a spectrum of the light source is used to calculate directly, errors will be caused in the calculation result of the chroma of the liquid crystal display, thereby affecting product quality and production efficiency.